accustomed vs routine

accustomed

adj
  • Familiar through use; usual; customary. 

  • Familiar with something through repeated experience; adapted to existing conditions. 

routine

adj
  • Regular; habitual. 

  • Ordinary with nothing to distinguish it from all the others. 

  • According to established procedure. 

noun
  • A course of action to be followed regularly; a standard procedure. 

  • A set piece of an entertainer's act. 

  • A set of normal procedures, often performed mechanically. 

  • A set of instructions designed to perform a specific task; a subroutine. 

How often have the words accustomed and routine occurred in a corpus of books? (source: Google Ngram Viewer )